FOCUS – The American health authorities justify this measure on the basis of a figure: 10% of contaminations would take place in the open air. A proportion which is very exaggerated compared to reality.
Guest of BFMTV on Monday, May 17, the Minister of Health Olivier Véran promised that wearing a mask outdoors would not be “soon»More compulsory in France – while being careful not to specify the date he plans to lift this ban, which concerns most French cities but also many places for walking, such as Le Figaro As shown, for example, in this infographic listing all the beaches where it is mandatory to keep your mask.
In detail, the Minister nonetheless distinguished the case of beaches from that of town centers: “When you are outside, with lots of shops, you will queue outside, you will eat, you will meet people, etc. There, as long as we do not have an adequate level of vaccination coverage, it seems more prudent to maintain the obligation to wear a mask“, He detailed, adding that on the other hand”if you are alone or a few in a very large space, very ventilated like a beach, a mountain, a forest, a park, a deserted street, there we must be able to be quickly brought to reconsider the obligation of the wearing of the mask in this situation“.
“QuicklySo, but not right away. Why that ? In fact, there are still a few scientific voices that timidly support the obligation to wear the mask outdoors, but they are fewer and fewer and do not always invoke the arguments that we believe. A study by Chinese scientists has, for example, established that by wearing a mask all the time (and therefore also outdoors), we are less likely than usual to touch our face with our hands – which can be a source of contamination. when these have been infected by our environment and we wear them in our nose or mouth. Moreover, in France, many infectious disease specialists have recommended wearing a mask outdoors as a way to get used to the mask and therefore to think about it systematically when you are indoors or in close proximity to people. other people. With our colleagues from Release , virologist Bruno Lina believes that this measure allows “adopt” a “reflex”And will encourage people to keep their masks more in an enclosed environment.
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Very little outdoor contamination
Other doctors, on the other hand, have repeatedly said since the start of the pandemic that the mask outdoors is a useless gadget, imposed by a precautionary principle taken to the extreme. In our columns, Dr Guillaume Barucq was – among others – their megaphone, writing in a forum that “wearing a mask outdoors has become a more political measure than a health measure, a showy measure that gives a false sense of security»And further specifying that inhaling the fresh air, the sea air in particular, is, on the contrary, more than recommended.
The main argument supporting the uselessness of wearing a mask outdoors remains above all the very low number of contaminations recorded outdoors. As we explained in particular in March (when the walks of Parisians along the banks of the Seine sparked controversy), no open-air cluster has been explicitly identified by Public Health France since October 2020 . A study by Professor Arnaud Fontanet also revealed last December that these contaminations certainly represented much less than 2% of all contaminations. Mostly, this number actually doesn’t mean much, since outdoor situations are very varied and only prolonged promiscuity with other people (in a crowd, a queue, etc.) or sharing a meal, for example, entails proven risks of contamination.
However, as explained in particular by New York Times , the American CDC (Centers for Disease Control, the equivalent of our Regional Health Agencies) continue to impose the wearing of masks outdoors on people not yet vaccinated, on the basis of a spurious figure. We would count “just under 10% of virus transmissions outdoors“, According to Dr. Rochelle Walensky, director of the CDC, in an official communication of April 27, relayed on the site of the White House.
However, this figure does not hold water. The American journalist David Leonhardt has indeed sought the studies at the origin of this calculation, the result of which is contradicted by all the epidemiologists he interviewed. The reality would be a hundred times lower: around 0.1% only of contamination outdoors, according to him.
So where does this gross error come from? Two studies in particular seem to count a surprisingly large number of outdoor contaminations: one from the Medical Research Council published in June, the other from the University of San Francisco published in February. What these two studies have in common: all the outdoor clusters identified were located … in Singapore. Would the air of this country be more foul there than elsewhere? Undoubtedly not: quite simply, the nomenclature used to count the clusters there considers all the sites as places of outside. The cases listed are therefore automatically counted as outdoor contaminations … which is very probably not the case for most of them.
Most contaminations take place outside the home, but it cannot be deduced that they take place in the open air.
Citing other studies this time, the journalist adds that many academics have a very broad view of “outdoor places», And sometimes include even places of work, leisure, commerce, etc. In short, all places located outside … the home, but not necessarily in the open air. The bias is therefore this: we are certainly right to consider that most contaminations take place outside the home, but we cannot deduce from this that they take place in the open air, or at least this indicator does not. not enough to justify specifically requiring the wearing of a mask in the open air.
Wearing a mask outdoors has no impact on the epidemic
Also a figurehead of the opponents of the mask in the open air, Dr. Martin Blachier believes for his part that it is not the epidemiological studies that are the most relevant on the usefulness of wearing the mask outdoors, because they are still too imprecise. Admittedly, when we examine in detail the places of contamination, we find a very low number of contaminations outside. But it is the physical knowledge of the modes of transmission of the virus that reveals it best, he explains: “Examination of the transmission by aerosols (these small invisible particles suspended in the air) shows that when you are a little far away and outdoors, the risk of contamination becomes minimal.»He explains to Figaro. And to add: “Imposing the wearing of a mask outdoors is a misnomer in terms of health, not only because it is useless but above all because it can risk dissuading us from going out when, on the contrary, it is the best thing to do: go to the big picture air and breathe!“
Finally, proof, if one was needed, that the obligation to wear a mask outdoors has no real epidemiological impact: analysts Serge Blondel and Samra Bouazza compared last December in Le Figaro the evolution of the epidemic in different territories, some concerned by the obligation to wear masks in the open air, others not: not only are the territories not experiencing major differences in the spread of the virus but, in addition, rather, it is those where the mask was not mandatory that experienced faster epidemic progression.
As a result of this increasingly general questioning of the interest in wearing the mask outdoors, local authorities are already starting to lift the obligation here and there in France, as in the Creuse from Thursday for example, as has just announced this Tuesday the prefect Virginie Darpheuille on France Bleu.